The present invention relates to an apparatus for driving a threading cutter, in particular, a motorized apparatus for driving a tap tool for threading or rethreading a bore wherein the apparatus provides an adjustable frame for bracing the apparatus against counter rotation induced by the cutting force of the tap tool.
In industrial and power plant applications, the rethreading of bores for acceptance of threaded studs or bolts is often needed. The rethreading or the cutting of threads in these bores is a laborious task requiring high torque to cut the threads. Where manually driving the tapping device with a lever arm is not practical or sufficiently rapid, a motorized tap driving apparatus is used. Typically these motorized tap driving apparatus have a high torque motor applied to a gear reducer/clutch which drives the tap tool. Such motorized tap tools require a means to brace the frame of the motor to prevent counter rotation of the frame caused by the resistance of the tap tool to rotation due to friction or cutting force in the cutting operation.
Known methods of bracing the motor frame against counter rotation lack sufficient flexibility to adapt the apparatus to various close quarters and configurations which require retapping of bores.
Generally, each tap tool is useful for cutting threads of a particular diameter. Different tap tools are required for different diameters. The tap tools have a polygonal end which is engaged with an adapter to connect with a rotating driving protrusion on the motor. The different diameter tap tools have different sized ends, requiring different adapters for each tap tool.